Rotary grate gas producer



SeP'f- 15, 1958 P. vAN ACKEREN 2,852,357

ROTARY GRATE GAS PRODUCER Filed Feb. l, 1955 ROTARY GRATE GAS PRDUCER Application February 1, 1955, Serial No. 485,536

3 Claims. (Cl. 445-66) This invention concerns rotary grate gas producers of the kind having a central grate and an annular grate plate pan mounted for rotation below the central grate at the lower end of the shaft of the producer and adapted to support the charge in such shaft.

Hitherto gas producers of the above-described kind have been furnished with a lower central plate or pan beneath a central aperture located in the annular grate plate pan under the central grate, the charge residue, hereinafter for convenience referred to as ash, falling through the central aperture in said annular grate pan and on to the said lower central plate. The intention of such an arrangement is to provide for uniform distribution of the gasification medium throughout the charge in the shaft of the producer but to obtain uniform gasification of the charge, it is not only necessary to obtain a uniform distribution of the gasification medium through` out the charge but it is also necessary that the ash shall be uniformly withdrawn from the shaft.

The object of the present invention, therefore, is to provide a rotary grate construction in which uniform withdrawal of the ash from the pro-ducer shaft may be obtained whilst providing for uniform distribution of the gasification medium throughout the charge in the producer shaft.

In accordance with the present invention, therefore, I provide a rotary grate gas producer of the kind described, characterised by a stationary conical central grate arranged above the central aperture in the rotary annular grate plate, this stationary conical grate having grate openings therein for the passage of gasification medium therethrough and being adapted to guide the downiiowing ash onto the annular rotary grate plate, in combination with strippers for discharging the ash over the inner and outer peripheries of the annular rotary grate plate.

Such an arrangement provides for uniform discharge of the ash from the bottom of the charge in the producer shaft whilst interfering with the uniform distribution of gasification medium throughout its cross-section, and by means of the said strippers, the discharge of ash can be accurately regulated in accordance with the operational characteristics of the producer at any time.

ln accordance with a further feature of the invention, the said rotary grate construction and the strippers associated therewith may be disposed within a gas-tight housing at the base of the producer, this housing being furnished at its lower end with a discharge aperture having suitable closure means. Such an arrangement is of particular advantage in the case of high-pressure gas producers and also for producers in which poisonous gases, for example technically pure carbon monoxide, are produced and in which all the gasification medium (carbon dioxide in the case of producers of pure carbon monoxide) is introduced into the shaft from beneath the central grate.

In accordance with yet another feature of the invention, the aforesaid gas-tight housing may conveniently 2,852,357 Patented Sept. 16, 1958 comprise an intermediate portion arranged between an upper portion which is rigidly `connected to the base of the producer shaft and a lower and stationary portion, the said intermediate portion being gas-tightly sealed to said upper and lower portions by means of liquid seals and being rigidly connected to the annular rotary grate plate for rotation therewith. Such an arrangement has the advantage that the drive means for the annular rotary grate plate can be connected to the said intermediate portion and thus avoid the need for drive shafts or the like passing through the housing and requiring seals which are difficult to maintain in gas-tight condition without continual maintenance and supervision.

An embodiment of the invention is illustrated by way i of example in the accompanying drawing wherein Fig. l

is a vertical sectional view ofthe gas producer; and Fig. 2 is a perspective view of the grate and ash supporting structure.

In the accompanying drawing, there is illustrated a rotary grate gas producer comprising a refractory shaft housing wall 1 enclosed by a metal jacket 2 and defining l a fuel bed space or shaft 3. The upper end of the housing 1 is connected to a charging device which comprises a charging pipe 4 projecting into the shaft chamber 3 and an intermediate container 6 which is shut off from the v pipe 4 by means of a conical valve 5.

The lower end of the shaft housing 1 is provided with a combined grate structure and ash receiving and discharging device generally indicated by the reference 7.

The grate structure comprises a rotary annular grate bed plate or pan ti, having above its central aperture 9 a stationary conical central grate l2, the latter being secured by means of a spider 10 to a dependent extension 11 coaxial with the shaft housing casing 2. The conical central grate 12 is provided with grate openings 13 for the passage therethrough of the gasification medium.

A stationary ash receiving housing portion 14 is gastightly connected to the shaft casing extension 11, this housing portion 14 having an inverted frusto-conical form. Beneath the ash receiving housing portion 14 is arranged a rotatable intermediate ash receiving housing portion 15 which is also of inverted frusto-conical form,

this intermediate portion 15 terminating at itslower end in an ash discharge aperture 16. A flat annulus 17 is rigidly and gas-tightly connected to the lower end of the intermediate ash receiving housing portion 15 Vand is provided on its underside with a ring of gear teeth 18 meshing with a pinion Ztl on a driving shaft 19.

A stationary lower ash discharging housing portion 21 is disposed beneath the annulus 17 and is equipped at its upper end with an annular sealing trough 22 containing water and into which dips a dependent rib 23 on the annulus 17 to form a gas-tight seal bel tween the intermediate ash receiving housing portion 15 and the lower ash discharging housing portion 21. A

gas-tight seal between the intermediate ash receiving housing portion 15 and the upper ash receiving housing portion 14 is provided in a similar manner by means of sealing trough Z4, as clearly shown in the drawing.

The lower ash discharging housing portion 21 is furnished with a conical valve 25 which can be raised and lowered and serves to close and open an aperture in the base of a hopper 26 within the upper end of the lower ash discharging housing portion 21.

The ash falling from the annular rotary grate plate 8 passes through the hopper 26 under the control of the valve 25 and into the lower part of the ash discharging housing portion 21. When the valve 25 has been raised to seal the lower end of the hopper 26 the ash in the lower ash discharging housing portion 21 below the valve 25 may be discharged past a segmental baie 27 and through a discharge aperture provided with a door 28 which serves to seal the lower ash discharging housing portion against ingress of air or escape of gasication medium when the valveZS is lowered.

The charge Vwithinthey fuel bed shaft 3.of the producer casing 1 is supportedjointly by the rotary annular grate plateor bed ,plate 8` and .the stationary central conical grate 12; the ash *which Ais formed at the base of the fuel bed-in shaft 3 is discharged at 8 over the outer peripheryof the annular rotary grate plate or pan 8 and also through the central aperture 9 of the latter `in .a manner hereinafter to bedescribed.

As the. ash falls from the rotating plate 8, the charge of fuel descends in the shaft 3 and the vash at thebase of the charge is diverted Idownwardly and .outwardly from the centre of the fuel .charge by the stationary central conical grate 12 and downwardlyand inwardly from the periphery .of the charge of fuel by means of a frustoconical deflector 3i? adjacent to the wall of the extension 11 just above the rotary grate plate 8. Thus vthe ash is confined to an annular throat 29 which converges vdownwardly in cross-section so that the ash is deposited finally in a band around the annular rotary grate plate 8, the throat29 diverging downwardly, as indicated `at 31, just above the rotary grate plate 8.

A plurality of outer strippers 32 are arranged around the annular rotary grate plate 8 adjacent to the upper surface of the latter. The strippers 32 are carried by the upper stationary ash receiving housing portion 14 and are adjustable radially inwardly and outwardly of the grate plate 8 by means of hand Wheels 33.

A plurality of inner strippers 34 carried by vertical arms 35 on horizontal spindles 36 are disposed over the rotary grate plate 8 adjacent to the inner margin thereof, the strippers 34 being adjustable radially inwardly and outwardly of the grate plate 8 by adjustment of the spindles 36 by means of hand wheels. By appropriate adjustment of the strippers 32 and 34, the rate of discharge of ash from the grate plate 8 can be adjusted and the proportions of the ash discharged over the inner and outer margins respectively of the grate plate 8 can be varied. In this way it is possible to ensure that the ash formed at the 'base of the charge in the shaft 3 is discharged uniformly over the whole cross-section of the charge of fuel and that the fuel charge descends uniformly throughout its cross-section.

During operation of the producer, gasication medium such as air, steam, 4carbon dioxide orother gas is introduced into the producer through one or more pipe connections 38 in the upper stationary ash receiving housing portion 14 and passes through the slots 13 in the stationary conical grate 12, thence through the ring of ash at the base of the charge surrounding the stationary conical grate 12; thereafter the gasication medium passes upwardly 4 through the charge, uniformly distributed over the full cross-section of the latter.

The rotary grate plate 8 is secured to the intermediate\ housing portion 15 and rotates therewith, this housing portion 15 being driven by rotation of the shaft 19.

What I claim is:

1. A rotary grate gas producer comprising a shaft casing forminga fuel bed shaft having at the lower portion thereof an annular rotatable plate in a horizontal plane with a central opening and with its outer periphery inwardly spaced from said casing to define an outer free space around the plate, said plate being adapted to support a fuel bed in the shaft, means for rotatably mounting said plate, means for rotating said plate, a stationary upwardly tapered grate provided with means for stationarily mounting the same, said stationary conical grate being arranged above the central opening in the rotary plate and provided with openings for passage of gasiiication media therethrough and having its lower periphery intermediate the inner and outer peripheries of the annular plate and at a distance above the same to guide the downiiow of ash onto the rotary plate, and inner and outer ash strippers for directing ash to the inner and outer peripheries of the rotary plate where they discharge over the inner and outer edges by gravity through the central opening and the outer free space.

2. Gas producer apparatus as claimed in claim l, and which includes a gas tight housing at the base of the producer', said housing having at its lower end an ash discharge means with closure means therefor, said rotary plate and the ash strippers therefor being disposed within the upper part of the gas tight housing above the ash discharge means at the lower end of the housing.

3. Rotary grate gas producer as claimed in claim 2, and in which the housing comprises an intermediate rotatable part which is rotatably mounted and provided with drive means on the outside of the same, said intermediate part being sealed by an immersion dip trough in a lower stationary sluice discharge part of said ash discharge means, said intermediate part being connected with the rotating plate, the plate being in an upper stationary part of the housing which is stationarily connected with the base of the gas producer shaft casing and the upper stationary part being provided with a sealing trough rigidly arranged at the bottom thereof for dip sealing relation with the intermediate rotatable part of the housing.

References Cited in the rile of this patent UNITED STATES PATENTS 399,795 Taylor Mar. 19, 1889 565,048 Taylor Aug. 4, 1896 1,008,833 Levin Nov. 14, 1911 1,655,320 Lummis Jan. 3, 1928 2,289,347 Daae July 14, 1942 

1. A ROTARY GRATE GAS PRODUCER COMPRISING A SHAFT CASING FORMING A FUEL BED SHAFT HAVING AT THE LOWER PORTION THEREOF AN ANNULAR ROTATABLE PLATE IN A HORIZONTAL PLANE WITH A CENTRAL OPENING AND WITH ITS OUTER PERIPHERY INWARDLY SPACED FROM SAID CASING TO DEFINE AN OUTER FREE SPACE AROUND THE PLATE, SAID PLATE BEING ADAPTED TO SUPPORT A FUEL BED IN THE SHAFT, MEANS FOR ROTATABLY MOUNTING SAID PLATE, MEANS FOR ROTATING SAID PLATE, A STATIONARY UPWARDLY TAPERED GRATE PROVIDED WITH MEANS FOR STATIONARILY MOUNTING THE SAME, SAID STATIONARY CONICAL GRATE BEING ARRANGED ABOVE THE CENTRAL OPENING IN THE ROTARY PLATE AND 